1. Field of the Invention
The present invention relates to a rubber hose material and a rubber hose formed by using the same.
2. Description of the Art
Heretofore, as a rubber material for forming a rubber hose, a material where a filler (such as carbon black) and a plasticizer (such as oil) are blended into an ethylene-propylene-diene terpolymer (EPDM) has been used (see, for example, Japanese Unexamined Patent Publication No. 10-180941). However, a rubber hose formed by using such a material has low hardness and thus is inferior in mechanical strength.
There are methods for raking a rubber hose harder. For example, in method (a), the amount of carbon black to be blended into the rubber material is increased or the amount of oil to be blended into the rubber material is decreased. In method (b), crosslinking density is increased by increasing the amount of a vulcanizing agent or a crosslinking agent to be blended into the rubber material. In method (c), a resin such as polypropylene or polyethylene is blended into the rubber material.
However, since the viscosity of the unvulcanized rubber is increased in the above-mentioned method (a), processability is remarkably aggravated. Since the anti-scorching property lowers and the crosslinked rubber turns into a resin state (or an ebonite) in the above-mentioned method (b), an intrinsic property of rubber (elongation) deteriorates. Further, there is the problem that dispersibility of a resin such as polypropylene or polyethylene deteriorates in the above-mentioned method (c). Thus, the current situation is that a rubber hose material is not available where a rubber property (elongation) is retained in the resulting rubber hose and excellent mechanical strength is also imparted to the resulting rubber hose. Therefore, there has been a demand for such a rubber hose material.
In view of the foregoing, it is an object of the present invention to provide a rubber hose material which makes it possible to form a rubber hose where the rubber property (elongation) is retained and which is excellent in mechanical strength, and a rubber hose obtained by using the same rubber hose material.